Automatic inflater for pneumatic tires



April 2, 1929.

H. A. CASE AUTOMATIC INFLATER FOR PNEUMATIC TIRES Filed April 21, 1928 Patented Apr. 2, 1929.

.stares innen A. casu, orv Los AiGnLiis, CALIFORNIA. l

AUTOMATIC INFLATER FOR PNEUMATIC TIRES.

y Application led April 21,

This invention relates to a device adapted to be attached to the wheel oi the motor vehicles tov automatically maintain the tires thereof in a properly inflated condition.

'fhe invention provides improved means to prevent tire leaks due to punctures or other causes, jfrom injuring the Ytire casing, as said casing will automatically be suppliedV with an amount et air suliicient to prevent any ordinary leali 'from causing deflation, thus making it unnecessary for the autoist to travel with a ilat.tire until he has an opportunity to repair an injured'one. y

VAn important object of the invention is to simplify the means :tor attachingan appliance of this kind to the wheel of a self-propelled vehicle. Byv thisy invention anv air pump construction lis provided which can be easily attached to the wheels of automobiles now on the market without any reinodelling of or alterations in such wheels.

A further object is the provision of an improved contrivance 'for automaticallyV disconnecting the pump operating means when the air pressure within the tire reaches the desired amount and also to automatically place the pump into operationL again when such air pressure becomes too low'. K

f Other objects and advantages may hereina'lfter appear. f

Referring to the accompanying drawings, which Villustrate a preferred embodiment oi' the invention. Y Y

Figurel, is a vertical mid-section of my newly invented air pump showing theparts thereof in the operating position which they automatically assume when the air pressure within the tire of the wheel to which the appliance is assumed to be attached has fallen as low as the appliance is adjusted to permit.-

A fragment of the'brakeband is also shown in this view. 1

Figure 2, is a like section but showing the position which the parts automatically as-k sume when the'puinp has been rendered inactive by reason of the required air pressure having been supplied to the tire.

Figure 3,is a perspective View of an-auto l mobile wheel illustrating the means for attachment of the appliance thereto.

Referring in `detail to the drawings, theV cylindrical pump casing 5, Vshown attached between the wheel spokes 3, is provided with leas. sei-iai No. 271,760. Y

the radially extendingv oppositely disposed.

outer arms 7 and the somewhat shorter arms 8, said arms 8 being located near the inner end of the casing, by the inner endbeing meant the venol nearest the brake band'9 of the wheel. f

'Arms 7 and-8 are respectively provided with bolt or screw holes 7b and 8"` whereby the appliance yis boltedto. the Wheel or is secured thereto in any other desired manner. It is to be understood that the appliance'is designed to be attached to disc wheels and also various other designs of vehicle wheels now on the market.

Within said casing 5 is an auxiliary piston chamber 10 having an lauxiliary pistonV head screwed into one end vthereof a piston rod 12 which, at its lower end as viewed in Figs. 1 and 2,-has a head ladapted to receive a screw-driver whereby the distance which said Y piston rodprojects from the piston head 11 may be regulated. i

The head 13 of pistonrod 12 is contained 'within a bore 15 within a plunger or main piston 16 which is slidably fitted within the end portion of the main casing` 5, .said bore being provided'with a contracted portion or neck 17 wit-hin which the piston rod 12 may reciprocate, and with an annular shoulder 18 which the head 13 at times engages. Chamber 45 above plunger 16 contains a compression springV 20 which'tends at all times to force said plunger toward the brake band 9, an annular groove 21 around the bore 15 forms a seat for spring 2O and also provides more longitudinal space for. said spring to increase its operative eiiiciency. f I

Within the outer or lower end of plunger 16 is a semi-circular recess 23 within which ismounted an antiiriction roller v24 on a pintle 25 which extends transversely of the plunger and which maintains said roller in j a position wherein a portion-of its peripheryI ate cam 26 formed on or secured to the brake band 9. i

Resuming description of the auxiliary pis-v ton head 11, said head is provided at one side with acentral stem or extension 30, said stein containing a longitudinally extending concavity or recess 31 Within which is pivoted on a transversely extending pin 32 an upwardly extending (as viewed in the drawings) dog 33, said dog having at its lower end a heel 34 which keeps its :tree end from swingingcompletely out of said recess. Stem 30, together with dog` 33, play through a guide nut 35 which is screwed intorthe main casing` 5. A. compression spring 3G operates between nut 35 and piston head l1, and a U-shaped leaf 'spring` 33' continually tends to 'force the ipree end ol' dog' 33 out of recess 3l and into a position wherein said dog` will either engage or 'underlie va spherical plunger 40 which forms a portion of the governing device next to be described. Said governing device comprises an entern'ally'threaded tubular member il which extends through a rY dial threaded aperture in the main casing, and 'which contains ie compression spring l2 which continually presses upon vball plunger Ll0, and the manually adjustable threaded stein which ei ythe outer end of said spring Vand regulates the tension 'thereo i?. f Y

As shown in i, the space between the inner endottulbular member il and the ad' jacent side olf stein 3() is sufficiently narrov.'

to 'keep ball i0 in place, and said stein never retracts liar enough to permit the escape oi said ball. "W hen the. coiicavity 3l is oppositesaid ballthe latter engages the outer edge of dog 33. rr capi()o having a relief port l0 is screwed into the upper end oi:` the main casing. l

Vithrepgard 'to ports andair passage" take ports Zilf'lead into the main piston ci ,mber i5,*said ports being located at points slightly above the main piston or plunger lo whenisaid piston isat the downward liit 'i its travelas seen in Fig. l. intake ports LiL-fl lead 'from van external annular recess fill which vis covered by 'a iiorainiiiatei and Ghainberli is also provided, it stop, with abl'eed duet and 'with an annular outlet passage i7 around the piston rod l2. Above outlet pas age Y is a check valve i8 which permits air to pass from chamber i5 to chain ber lGybut prevents bach iiow from the latter chamber. i9 is an outlet passage from chamber 10 to conduct air by way of the i ibletube 50 to the `tire 5l. 43 is a retai plug 'for 'val-ve 48. 1

rlllie movement of plunger 13 toward the hub'of the wheel isy limited by a screw bolt 55 which projects through the casinpl wail into agroovetlin the side oi said plunger.

Packing` elements 60, 6l and are providedv for the pistons. rllhe lower end el bore 2145 is closed'by a screw plug A. ln operation, at each revolution of the vehicle wheel to which the appliance 'is attaclied, the roller is moved across cam 26 ily/eases D plunger 16 against the opposition. or spring` 20, closing` ports all and then forcing past check valve i8 into chamber l() a portion the air conned in chamber 45. ln leavingl cam 26, roller Q4- permits spring 20 to restore plunger 16 again to its extended position before the Aroller 2li re-engages cam A?. i I, this movin0 lrhese movements of plunger 16 are repeated until a sullicient amount of air from he chamber i0 of the auxiliarv piston has een rorced into the tire to raiseV the air presure, both within thev tire and within chamiary piston bead 1l to overcome the resistance oi' spherical plunger Ll() to its 33,

- whereupon the auxiliary piston and the parts carried thereby will move quickly up from the position of Fig. l to that or" liig. 2, thus through the operation of rod l2 and its head 13 bringing tliemain piston loup Vto the inoperative gef The ports will remain in this position until the air Apressure in the tire, and thereiore in chamber l0, ialls suiiicie'ntly to 'allow the compression springs-35 and 20 kto restore y both pistons to their originalpositions.`

'ilie cani i-or actuatingl the appliance maybe attached to any other conveniently located stationary part ii it cannot. be placed on the brake band.

l claim: f Y

i. lin a device oi' the character'described,a tubular casing having,^ in lone kportion oi its length :i main piston chamber and Ainianother portion ofitslength an auxiliary'piston'chain-l ber, a main pistonandan auxiliary piston Ito operate respectively in said main and auxiliary chambers, cam operable means {opera-Y .iition thereof as shown in Fig.'

per lG, to 'a point which will cause the auxil 'y permit a .sudden lrelease movement of :said Y auxiliary piston yaway from the air pressure thereagainsi; when said air pressure exceeds a predetermined amount and to permit its return under the pressure of its spring' when the air pressure falls again, and meansoperatively connecting said auxiliary ,piston withV said piston whereby said releasemo'venient afforded by said governing device'moves said main piston to -a position wherein its cam-operable means are rendered inactive.

2. In a device of the character described, the combination, with main and auxiliarypis tons, cylinders for said pistons, and means to operate said main piston to pump air into the Vmomo@ -auxiliaryipiston chamber; of a governing device-for said auxiliary piston, said governing device having ai plunger which travels in a plane transverse tothe axis of said auxiliaryl piston and which maintains said auxiliary piston in normal position until said auxiliary piston is forced past it to an inoperative position by air pressure in saidauxiliary chamber, connecting means between said pistons to c ause this movement of said auxiliary piston to move said main piston to an inoperative position, 'and means to restore bothl of saidk pistons to the operative position againstthe opposition of said'governor when the air pressure in said .auxiliary chamber falls to a predetermined amount. v

3. In a device of the 6character described, the combination, with main and auxiliary pistons, cylinders for said pistons, and means to operate said main piston to pump air into the auxiliary piston chamber; of a governing device for said auxiliary piston, said govern' ing device having a plunger which travels in a plane transverse to the axis of said auxiliary piston and which maintains said auxiliary piston in normal posit-ion u'iitils'aid auxiliary piston is forced past it to an inoperative position by air pressure in said auxiliary chainber, connecting means between said pistons to cause this movement of said auxiliary piston to move said main piston to an inoperative position, and means to restore both of said pistons to the operative position against the opposition of said governor when the air pressure in said auxiliary chamber falls to a predetermined amount, said governing device comprising a tube having an open end portion'- and the said plunger thereof being a spherical body, a compression spring within said tube of said plunger which holds said spherical body projected more or less beyond the open end of said tube, a dog in said auxiliary piston provided with a spring ywhich yieldingly holds said dog in a position wherein its travel together with that of theauxiliary piston is yieldingly obstructed in both direc-` tions by said spherical body;

4. In a device of the character described,

kthe combination, with main and'auxiliary pistons, cylinders for said pistons, and means to operate said main piston to pump air'intorthe auxiliary piston chamber; of a governing device for said auxiliary piston,'said governing device having a plunger which travels in a plane transverse to the axis of said auxiliary piston and which maintains said auxiliary piston in normal position until said auxiliary piston is forced past it to an inoperative position by air pressure in saidV auxiliary chamber, connecting means between said pistons to cause `this movement of said auxiliary pis,-V

ton-to move said main piston to an inoperative position, and 'means to restore both of said pistons to the operative position against the opposition of said governor when the air pressurein said auxiliary chamberkfalls to a predetermined amount, adog inV said auxiliary piston kwhichis carried thereby, when ,the main piston is operating, the free end of said dog being in lateral engagement with the plungerof said governing device and beingl constructed and arranged to slide over and beyond said plunger when impelled by a predetermined amount of pressure from the air accumulated in the auxiliary piston chamber,

` the side of said dog after it has been moved i beyond said plunger engagingthe latter and oii'ering a predetermined amountV of resistance to the return movement of said auxiliary vstein or its appendages from escaping from said tube, a compression spring within said r`tube engaging said spherical plunger, there being a recess inthe side of said stem, and a spring pressed dog mounted in said recess, said dog being positioned to encounter said spherical plunger andV thus yieldingly oppose force tending to move said auxiliary piston away from its retracted position'and also to encounter said spherical plunger and yield- '.ingly oppose force tendingto move said auxf `iliary piston away from its extended position.

6. In a device of the character described, control mechanism comprising an auxiliary piston having a stem with a recess in it-s side,

a spring actuated dog in said recess and extending longitudinally of said stem but iiiclined in such a manner that its free end proti'udes beyond said recess, and a governing device comprising a spring pressed spherical vplunger and a tubularhousing positioned to yieldingly holdffsaid plungerV against the recessed side of said stem 'in position to govern the movement of said stem and dog back and Y forth across said plunger.

7.- In a device of the character described, a casingcomprising a main piston chamber and a control piston chamber separated by'a cross wall having an air passage therethrough, a check valve in said passage through which the air flows from Vsaid main to said control chamber, a piston in each ofV said chambers,

' cam actuated means to move to retracted position the piston in said main chamber, and a compression spring acting between said cross wall and the main piston to extendthe latter,

saidmain piston'comprising a plunger hav` ing in one end an annular groove in which said spring seats and which is of suijlicient depth to receive the greater portion of said spring.

' 8. In a device of the character described, a casing comprising` a main piston chamber and a control piston chamber separated by a cr Wall having an air passage therethrough, a check valve in said passage through which the air ilovvs from said main to said control chamber, a piston in each of said chambers, cam actuated means to move to retracted position the piston in said main cha1nber,and a compression spring acting` bet-Ween said cross Wall and the main piston to extend the latter, said main piston comprising` a plunger having in one end an annular groove in which -said spring seats and which is of suilicient depth. to receive the greater portion of said spring, said plunger havinga bore, a. portion o1E Which is surrounded by said annular groove, an annular shoulder at the inner end of said bore, a control rod having` ahead Withrvozsoe in said bore adapted to engage said shoulder, and governing means toy aotuate said control rod. e Y

9. ln a device of the character described,

the combination, Withl main and auxiliary pistons, cylinders `iorsaid pistons, and means to operate said main piston to pui-np air into the auxiliary piston chamber; of a governing device for said auxiliary piston, which maintains said auxiliarypiston in normal position until said auxiliary piston is forced to an .inoperative position by air pressure in said auxiliary chamber, connecting meansbetvveen said piston to cause this movement of .Said auxiliary piston to move said main piston to an inoperative position, and means 'to restore both of sadpistonsuto the operative position against the opposition of said governor `when the air pressure in .said auxiliary chamber tails to a predetermined amount.

HIRAM A. CASE. 

